After the first refurbishment, waterproofing problems plagued a sandstone staircase, which leads down from a terrace at the back of the house to gardens, also protected by a preservation order, on the edge of the lake, plus the area above a nymphaeum. Cracks in the substrate had led to moisture infiltrating into the fabric of the structure. As there are living and ancillary rooms underneath the sandstone construction, re-waterproofing of the steps was essential. The first refurbishment attempt, in which the steps were removed completely and replaced on top of conventional waterproof sheeting, had failed.
In 2004 the waterproofing works were carried out with solvent-free KEMPEROL 2K-PUR, which could be applied to the sandstone without having to remove the steps. First of all, the staircase and viewing platform were sand-blasted before the absorbent sandstone surface was pre-treated with solvent-free KEMPERTEC EP-Primer to close all the pores. Then, the KEMPEROL 2K-PUR – the permanently resilient system that bridges over cracks – was applied to approx. 300 m². Hardwearing KEMPERDUR Deko in a pale sand colour was applied afterwards as a wearing course and KEMPERTEC NQ 0408 Natural Quartz was spread over this to create a non-slip finish. This was then finished off with a topcoat of KEMPERDUR Finish.
The use of a waterproofing material that can be applied as a liquid was not only the most reliable, but at the same time also the cheapest solution. As the building and surrounding gardens are protected by preservation orders, the right choice of wearing course had to be guaranteed so that the characteristic look of the sandstone was retained.